Centralizer for drill steels



Jan. 20, 1931. L. c. BAYLES 8 CENTRALI-ZER FOR DRILL STEELS Fileddune23, 1928 g INVENTO-R.

Iii/5 ATTORNEY.

. lie-um (113a Zed i v Patented Jan. 20, 1931 r V e v P i *UNITED STATESPATENT OFFICE LEWIS c. BAYLES, or EAS'ION, rENNsYLvnivia, Ass'renon roIivGEnsoLL-nAnn co u- PAN'Y, or JERSEY CITY, NEW JERSEY,ACOBJ?ORATIO1\Ion NEW JERSEY,

CENTRALIZER FOR DRI-LL STEELS Application-filed June 23, 1928. SerialNo. 287,766.

1 This invention relates to rock drills, but. plicity of illustration,but it is 'to' be undermore particularly to centralizer for the stoodthat-suitable elements, such asguides working implement, such as a drillsteel (not shown) on therock drill, of which the adapted to be actuatedby rock drills of the front head is a part, may interlock with the 5hammer type. V shell A in a wellknown manner to enable the 50 One objectof the invention is to guide and rock drill to travel longitudinally ofthe shell support the overhanging portion of the drill A. A .workingimplement E illustrated as a steel so that in' starting a drill hole thebit drill steel extends with its rearward or shank of the drill steelwill be held in axial alignend into the front head D to receive theblows ith th k d ill. of a hammer piston (not shown) of the drill. 55

Another object is to enable the centralizer In certain drillingoperations it is at times to be readily rocked out of the operative poamatter of considerable-difliculty to maintain sition by means of therock drill after the the drill bit coaxial with the rock drill,pardrilling operation reaches a point in which ticularly when the rockdrill lies in a horithe guiding function of-a centralizer is no Zontalposition or in positions, approaching '60 longer essential. thehorizontal; Aftera certain period of Other objects will be in partobvious and usage wear is caused in the chuck parts of in part pointedout hereinafter, and to all of the rock drill-and as a consequence the,drill these ends the invention consists of the feasteel tends toinc-line from the axis of the tures of construction and arrangement ofrock drill. When operating under these con- .65 parts having the generalmode of operation ditions the drill bit will swing about thedesubstantially as hereinafter described and sired axis in starting anew drill hole and as claimed and illustrated in the accompanying aresult the hole may incline from the indrawings, in which tended course.r 1 Figure 1 is a longitudinal side elevation of Frequently theforegoing conditions are l 70 the front end of a rock drill and itsshell not detected until a certain depth has been showing the manner inwhich thefree end drilled or until drill steels of greaterlength of thedrill steel is guided, have been substituted for the starting drill.Figure 2 is an enlarged longitudinal sec If their the position of thedrill is not changed tional; elevation of the centralizer and a portocoincide with the course of the drill hole 7 tion of the shell takenthrough Figure 3 on the'drill steel will bind in the drill hole and theline 22 looking in the direction indi will greatly hinder the rotationof the drill cated by the arrows, and 4 steel. 7 As a result of suchbinding of the drill Figure 3 is a transverse sectional elevation steelthe drilling efliciency will be considerof the centralizer taken throughFigure 1 on ably lowered, the drill bit will require more front head- Dis shown. for .thesake; of sim- The centralize! F comprises a yoke-G msthe line 33 looking in the direction indifrequentsharpening and it willalso be more cated by the arrows. difficult; to maintain thelgauge ofthe drill Referring more particularly to the drawbit than would be thecase if. the drill bit ings, A represents a rock drill shell having weremaintained in axial alignment with the a conical projection B wherebythe shell may rock drill. be secured to a support for holding the shell1 The present invention aims to eliminate in fixed position with respecttoa working the foregoing described undesirable features surface, suchas the rock designated-byC, and to this end the rock drill is provided 1In the drawings only the front end of a a with a centralizer designatedgenerally by F.

arms H of which are suitably spaced to receive the body portion of thedrill steel E. Preferably a U-shaped bushing J is dis posed in the yokeG to act as a wearing surface for the yoke, so that any wear which maybe caused by the drill steel E will be confined to the comparativelyinexpensive bushing J and which bushing may be readily V and cheaplyreplaced whenever it becomes unfit for the intended purpose.

In the construction shown the yoke G is provided with an integral stem Khaving at its lowermost end a transverse portionL in which is formed anaperture 0 for the receptionof a pivot pin Parranged transverse to andoff-set with respect to the axis of the drill steel for which the yokeforms aguide so that the said yoke will rock through'a plane extendingthrough the axis of the drill steel. The relative proportions of theaperture O and the pivot pin P are preferably such that the yoke G mayrock freely on the pin P.

The pivot pin P is seated with its ends into bearing blocks Q arrangedon opposite sides of the transverse portion L. The bearing blocks Qtherefore lie in the same transverse plane as the stem K and haveapertures B through which extend bolts S whereby the bearing blocks Q,are secured directly to the front end of the shell A.

If desired, or whenever the centralizer F is applied to certain types ofshells, spacers T may be interposed between the bearing blocks Q, andthe end of the shell to avoid contact between the centralizer and suchadjuncts as may protrude beyond the end of the shell,

as for instance, a feed screw bearing U which forms a support for a feedscrew V whereby the rock drill is actuated longitudinally of the shell.In order to maintain the pin P stationary in the bearing blocks Q, pinsW are disposed in the bearing blocks Q, to extend through the pivot pinP, thus holding said pivot pin P both against rotary and longitudinalmovement relatively to the hearing blocks Q.

Suitable means are provided for preventing unauthorized movement of theyoke G out of the operative position. To this end the stem K is providedwith an aperture X for the reception of a plunger Y having a flat end Yadapted to seat on a flat surface Z of the pin P. A spring 6 is disposedin the aperture X rearwardly of the plunger Y to exert a pressure onsaid plunger tending to hold it firmly against the flat surface Z. Ifdesired a similar flat surface 0 may be formed on the forward surface ofthe pin P to act as a seat for the plunger Y so that when the yoke G isrocked out of the operative or guiding position, said plunger maycooperate with the flat surface 0 for maining the yoke in theinoperative position in dicated by dot and dash lines in Figure 1.

In order to assure against movement of the drill steel in the directionof the open end of the yoke G a pin d may be inserted in apertures c inthe arms H of the yoke and said apertures e are preferably so locatedthat the pin d may bear lightly against the surface of the drill steelE. V

In the operation of the device, whenever it is desired to start a newdrill hole the centralizer F may be rocked to the operative position,thatis, to a position in which it lies perpendicular to the drill steelE. The pin d may then be inserted in the apertures e to maintain thedrill steel E in alignment with the longitudinal axis of the front headD. In this position of the centralizer the plunger Y will bear againstthe fiat surface Z and will be held in engagement therewith by thepressure exerted by the spring 6, it being assumed of course that thespring I) is capable of exerting a suflicient pressure to hold thecentralizer F in this position unaffected by the vibration set up in therock drill. As the front head D approaches the centralizer F the pin dmay be withdrawn from the aperture e and as the drill advances towardthe rock C the front head D will strike the centralizer F and will rockit to the inoperative position wherein it will be held by the springpressed plunger Y.

By means of this invention the front or free end of the drill steel mayat all times be held coaxial with the rock drill so that when the bitend ofthe steel encounters abnormalities in the rock being drilled thesteel will be held against departure from the desired course. This isparticularly desirable and advantageous in drilling operations whereinit is essential that the holes be drilled parallel to each other, as forinstance where the line of cut or drilling is later traversed by abroaching mechanism for removing the material between adjacent drillholes.

I claim:

1. A centralizer for drill steels, comprising a yoke for guiding a drillsteel, astem on the yoke having an aperture, a pair of bearing blocksadapted to be secured directly to the end of a rock drill shell anddisposed on opposite sides of the stem, a pin seated fixedly in thebearing blocks and extending through the aperture to form a pivotalsupport for the yoke, a fiat surface on the pin, and a spring pressedplunger in the stem having a flat end to seat on the flat surface fornormally holding the yoke against movement with respect to the pin.

2. A centralizer for drill steels, comprising a yoke for guiding a drillsteel, a stem on the yoke having an aperture, a pair of bearing blockssecured directly to the end of a rock drill shell and lying in the sametransverse plane as the yoke, a pin seated fixedly in the bearing blocksand extending through the aperture to form a pivotal support for theyoke, a flat surface on the pin, a spring pressed plunger in the stemseating on the flat surface to normally hold the yoke against movementwith respect tothe pin, a U-shaped bushing in the yoke forming a bearingsurface for the drill steel, and a pin insertable in the yoke formaintaining the drill steel coaxial with a rock drill whereby it isactuated.

In testimony whereof I have signed this specification.

LEWIS C. BAYLES. I

